If the rate law obtained for a given reaction is rate = k(X)n (Y)m, what is the overall order of the reaction?
- A. nm
- B. n/m
- C. n + m
- D. n - m
2SO2(g) + O2(g) → 2SO3. In the reaction above, the standard heats of formation of SO2(g) and SO3(g) are -297 KJ mol-1 and -396 kJ/mol respectively. The heat change of the reaction is?
- A. -99 kJ mol-
- B. -198 kJ mol-
- C. +198 kJ mol-
- D. +683kJ mol-
2H2S(g) + SO2(g) + H2O(I) → 3S(s) + 3H2O(I)……….(i) 3CuO(s) + 2NH3(g) → 3Cu(s) + 3H2O(I) + N2(g)………(II) In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?
- A. H2S and NH3
- B. SO2 and CuO
- C. SO2 and NH3
- D. H2S and CuO
What is the oxidation number of Z in K3ZCl6?
- A. -3
- B. +3
- C. -6
- D. +6
How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?
(Ni = 58.7, 1F = 96 500 C mol–)
- A. 0.20
- B. 0.30
- C. 0.40
- D. 0.50
When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively?
- A. acidic
- B. basic
- C. neutral
- D. amphoteric
Given that 15.00 cm3 of H2
SO4 was required to completely neutralize 25.00 cm3 of 0.125 mol dm-3 NaOH, calculate the molar concentration of the acid solution:
- A. 0.925 mol dm-3
- B. 0.156mol dm-3
- C. 0.104 mol dm-3
- D. 0.023 mol dm-3
Which of the aqueous solutions with the pH values below will liberate hydrogen when it react with magnesium metals?
- A. 13.0
- B. 7.0
- C. 6.5
- D. 3.0
The hydroxyl ion concentrated, (OH–), in a solution of sodium hydroxide of pH 10.0 is?
- A. 10-10 mol dm-3
- B. 10-6 mol dm-3
- C. 10-4 mol dm-3
- D. 10-2 mol dm-3
A saturated solution of AgCl was found to have a concentration of 1.30 x 10-5 mol dm-3. The solubility product of AgCl therefore is?
- A. 1.30 x 10-5 mol2 dm-6
- B. 1.30 x 10-7 mol2 dm-6
- C. 1.69 x 10-10 mol2 dm-6
- D. 2.60 x 10-12 mol2 dm-6
A major process involved in the softening of hard water is the?
- A. conversion of a soluble calcium salt to its trioxoncarbonate (lV)
- B. decomposition of calcium trioxocarbonate (lV)
- C. conversion of an insoluble calcium salts to its trioxocarbonate (lV)
- D. oxidation of calcium atoms to its ions
Which of the following gases is the most dangerous pollutant?
- A. Hydrogen sulphide
- B. Carbon (lV) oxide
- C. Sulphur (lV) oxide
- D. Carbon (ll) oxide
On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO4. yH2O. The value of y is?
(Mg = 24, S = 32, O = 16, H = 1)
- A. 1
- B. 3
- C. 5
- D. 7
200 cm3 of air was passed over heated copper in a syringe several times to produce copper (II) oxide.
When cooled, the final volume of air recorded was 158cm3. Estimate the percentage of oxygen in the air?
- A. 31%
- B. 27%
- C. 21%
- D. 19%
If 30cm3 of oxygen diffuses through porous plug in 7s, how long will it take 60 cm3 of chlorine to diffuse through the same plug?
- A. 12s
- B. 14s
- C. 21s
- D. 30s
Oxygen is a mixture of two isotopes 16-O and 18-O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?
- A. 16.0
- B. 16.2
- C. 17.0
- D. 18.0
Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound PxQY. The respective values of x and y are?
- A. 1 and 1
- B. 1 and 2
- C. 2 and 1
- D. 3 and 1
In the periodic table, what is the property that decreases along the periodic and increases down the group?
- A. Atomic number
- B. Electron affinity
- C. Ionization potential
- D. Atomic radius
The electron configuration of two elements with similar chemical properties are represented by?
- A. 1s22s22p5 and 1s22s22p4
- B. 1s22s22p4 and 1s22s22p63s1
- C. 1s22s22p63s1 and 1s22s1
- D. 1s22s22p4 and 1s22s1
The temperature of a body decreases when drops of liquid placed on it evaporate because?
- A. the atmospheric vapour pressure has a cooling effect on the body
- B. a temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
- C. the heat of vapourization is drawn from the body causing it to cool
- D. the random motion of the liquid molecules causes a cooling effect on the body
A mixture of 0.20 mole of Ar, 0.20 mole of N2 and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is?
- A. 0.90 atm
- B. 0.80 atm
- C. 0.70 atm
- D. 0.60 atm